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Fix 'Serialization Error Action Needed' in Ready or Not: Quick Guide

by Hunter May 07,2025

*Ready or Not* might sound like a kid's game, but this SWAT-themed FPS is anything but child-friendly. Whether you're diving into single-player missions or teaming up for multiplayer action, you might occasionally encounter technical issues. Here's a comprehensive guide on how to resolve the "Serialization Error Action Needed" in *Ready or Not*.

How to Tackle 'Serialization Error Action Needed' in Ready or Not

Photos of the Soft Objects for 23 Megabytes A Second in Ready or Not as part of an article about how to fix the 'Serialization Error Action Needed'Screenshot via The Escapist

The *Ready or Not* error "Serialization Error Action Needed" often comes with the message "Corrupt data found, please verify your installation." This issue is associated with the Unreal Engine, and there are several strategies to address it.

1. Verify Your Installation

The first step is to follow the error's suggestion and verify your game installation. Ensure Steam is not in offline mode and follow these steps:

  • Go to your Steam Library and locate *Ready or Not*.
  • Right-click on the game and select "Properties."
  • Click on "Installed Files."
  • Choose "Verify Integrity of Game Files."

This process checks for any missing or damaged files and will re-download them if necessary. After completing this, relaunch *Ready or Not*. If the error persists, further action is required.

2. Remove Any Mods

The "Serialization Error Action Needed" can be triggered by outdated or broken mods, particularly those not updated for Unreal Engine 5. Here's how to remove them:

  • Go to your Steam Library and find *Ready or Not*.
  • Left-click on "Manage" and then "Browse Local Files."
  • Navigate through the "ReadyorNot" folder to "Content" and then "Paks."
  • Delete the "mod.io" folder.

This should allow the game to run, but you'll be without your mods for now. So, what's next?

Related: Ready or Not: What's Better, DirectX 11 or DirectX 12 (DX11 vs. DX12)?

3. Reinstall Your Mods

To get your mods back, you'll need to reinstall them carefully:

  • Visit Nexus Mods, Mod.io, or your mod source and locate the mod pages.
  • Check the update date of each mod. If it was updated after July 2024, when *Ready or Not* switched to UE5, it should be safe to reinstall.
  • Install one mod at a time, launch the game after each installation to check for errors.
  • If the error reappears, the last installed mod is likely the culprit and should be skipped.

If these steps don't resolve the issue, consider a full uninstall and reinstall of *Ready or Not*. Although rare, hardware issues like a corrupted hard disk could also be a factor, but most cases are linked to outdated mods.

That's how you can fix the "Serialization Error Action Needed" in *Ready or Not*. The game is currently available for PC players.